We have an 11, going on 12 year old Dachshund. Whenever a new dog comes over, they sniff her woman parts a LOT, more than I would consider normal, and very frequently with intent. My childhood dog had bladder cancer, and our other dog would NOT stop sniffing her in the same way. Could this be a sign of something more serious or could it just be they are interested in 'getting to know her more.'
There have always been stories, rumors and even scientific literature of dogs that can sniff out all sorts of ailments, including cancer. Some cancers cause changes in the body that could feasibly be detected by other animals by altering what and how things are excreted from the body. For example, a bladder tumor may alter what is excreted in the urine, including causing blood to be mixed into the fluid and this could get the attention of another dog's nose. However, there are a lot of things that can cause changes to the urine that other dogs may find interesting that are not cancer, such as a urinary tract infection. In this way, one dog might spend a lot of time smelling another dog's lady parts, but it doesn't mean that it is because of cancer. It could be from any number of reasons, including just be really interested in lady parts!
For more reading, here is an interesting article on dogs being trained to sniff out ovarian cancer: http://well.blogs.nytimes.com/2014/09/10/training-dogs-to-sniff-out-cancer/?_r=0 (http://well.blogs.nytimes.com/2014/09...)
Here is a scientific article (British Medical Journal) demonstrating the possible role of dogs sniffing out bladder cancer: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC518893/ (http://www.ncbi.nlm.nih.gov/pmc/artic...)
If you are concerned about your Dachshund, maybe its time for a checkup with the vet.
no scientific evidence from me, but I've heard many stories of dogs doing/being able to "sniff out" illnesses. I have a chow chow that will let my neighbor pet her with his right hand only. his left hand had a cancer at some point but he's fine now, but she will back away if he tries to touch her with it. Other hand no problem! weird huh?